SPATIOTEMPORAL PATTERNS OF HIGH MARINE PRODUCTIVITY IN THE MAKASSAR STRAIT BASED ON CHLOROPHYLL-a AND SEA SURFACE TEMPERATURE IN 2005–2025

Abstract

The Makassar Strait serves as a crucial tropical marine corridor, exhibiting spatial and seasonal variations in productivity influenced by monsoon dynamics, ocean circulation, precipitation, and nutrient availability. This research delineated the spatiotemporal patterns of elevated chlorophyll-a concentrations in the Makassar Strait from 2005 to 2025, utilizing satellite-derived chlorophyll-a and Sea Surface Temperature (SST) data. Monthly datasets from Copernicus Marine and the Climate Data Store were examined at a resolution of 0.25° × 0.25°. High-productivity hotspots were identified using the monthly 75th percentile (P75) of chlorophyll-a, while climatological patterns and Pearson correlation analyses were employed to investigate temporal variability and its association with SST. High-productivity waters were predominantly located along the East Kalimantan coastal zone and the southern Makassar Strait, with local mean chlorophyll-a concentrations surpassing 0.5 mg m⁻³. Domain-mean productivity reached a peak of approximately 0.31 mg m⁻³ in March, whereas hotspot intensity was greatest in August (P75 = 0.220 mg m⁻³). SST values ranged from 28.4 to 29.9 °C, exhibiting a significant warming trend of approximately 0.02 °C per year (p = 0.00004). Overall, SST and chlorophyll-a demonstrated a negative correlation (r = −0.469; p < 0.05), although this relationship varied across different months. The findings highlight recurring productivity hotspots and seasonal variability, which can facilitate marine productivity monitoring and further evaluation of fisheries potential in the Makassar Strait.